CVE-2023-36804 is a use-after-free vulnerability classified under CWE-416 found in the Windows Graphics Device Interface (GDI) component of Microsoft Windows 10 Version 1809 (build 10.0.17763.0). This vulnerability allows an attacker with low-level privileges (local access with limited rights) to exploit the flaw to elevate their privileges on the affected system. The vulnerability arises from improper handling of memory in the GDI subsystem, where an object is freed but later accessed, leading to potential memory corruption. Exploiting this flaw can result in arbitrary code execution with elevated privileges, compromising system confidentiality, integrity, and availability. The CVSS v3.1 base score is 7.8, indicating high severity, with attack vector local, low attack complexity, low privileges required, and no user interaction needed. Although no public exploits are known at this time, the vulnerability is critical for systems still running Windows 10 Version 1809, which is an older, out-of-support version. The lack of patch links suggests that organizations should prioritize upgrading or applying any available security updates from Microsoft. This vulnerability could be leveraged by attackers to bypass security controls and gain administrative access, enabling further malicious activities such as data theft, system manipulation, or ransomware deployment.

For European organizations, this vulnerability poses a significant risk, especially those operating legacy systems or environments where Windows 10 Version 1809 remains in use. Successful exploitation can lead to full system compromise, allowing attackers to escalate privileges from a low-privileged user to SYSTEM level. This can result in unauthorized access to sensitive data, disruption of critical services, and potential lateral movement within networks. Sectors such as finance, healthcare, government, and critical infrastructure are particularly vulnerable due to the high value of their data and services. The vulnerability’s local attack vector means that attackers need some form of access to the system, which could be achieved through phishing, insider threats, or exploiting other vulnerabilities to gain initial foothold. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, as weaponization could occur at any time. The impact on confidentiality, integrity, and availability is high, making timely mitigation essential to prevent potential breaches and operational disruptions.

1. Upgrade affected systems to a supported and fully patched version of Windows, preferably the latest Windows 10 or Windows 11 releases, as Windows 10 Version 1809 is out of mainstream support. 2. Apply any available security updates or patches from Microsoft as soon as they are released. 3. Restrict local access to critical systems by enforcing strict access controls and using least privilege principles to limit the number of users who can log in locally. 4. Implement application whitelisting and endpoint detection and response (EDR) solutions to monitor and block suspicious activities related to privilege escalation attempts. 5. Conduct regular vulnerability assessments and penetration tests focusing on privilege escalation vectors. 6. Educate users about the risks of phishing and social engineering that could lead to initial local access. 7. Isolate legacy systems where upgrading is not immediately feasible and monitor them closely for anomalous behavior. 8. Maintain comprehensive logging and alerting to detect early signs of exploitation attempts.